docs: def parse_varbyte_as_int(self, fp, return_bytes_read=True):
          """Read a variable length byte from the file and return the
          corresponding integer."""
          result = 0
          bytes_read = 0
          r = 0x80
          while r & 0x80:
              try:
                  r = self.bytes_to_int(fp.read(1))
                  self.bytes_read += 1
              except:
                  raise IOError("Couldn't read variable length byte from file.")
              if r & 0x80:
                  result = (result << 7) + (r & 0x7F)
              else:
                  result = (result << 7) + r
              bytes_read += 1
          if not return_bytes_read:
              return result
          else:
              return (result, bytes_read)